Process for removing liquid from steatite.



BOTHO SCHWI E BIN, OF FRANKFORT-ON-THE-MAIN, GERMANY, ASSIGNOR TO ELEKTRO- OSMOSE AKTIENGESELLSGHAFT (GRAF SGHWERINGESELLSCHAFT), OF FRANKFORT- ON-THE-MAIN, GE, A CORPORATION.

PROCESS FOR REMOVING LIQUID FROM STEATITE.

nacasso.

Specification of Letters Patent.

' No Drawing. Application filed November 11 1914; Serial No. 871,626. Renewed October 24, 1917. Serial To all whom it may concern:

Be it known that I, BOTHO SGHWERIN, a

. subject of the German Emperor, residing at Frankfort-on-the-Main, Germany, have invented certain new and useful Improvements in Processes for Removing Liquid from Steatite, of which the following is a specification.

. The present invention relates to a process for removing of water from steat-ite by electro-osmosis. The invention relates particularly to a process by which, without increas ing the consumption of energy a considerable increase in the degree of dryness can be achieved in respect to the methods now known.

It has been found, that the electro-osmotic removal of water becomes the more efi'ective ,the more finely subdivided the material is; that is to say, as the smallness of the particles increases the extent to which the water is removed and the rapidity of the osmosis increase. The present improvement, therefore consists in comminutin the steatite to as finely subdivided condition as possible before subjecting it to the electro-osmotic process for removing water. The degree of fineness is limited by commercial considerations.

In the chemical treatment of colloids the efiect is frequently enhanced by adding to the colloidal body or to a suspension thereof,

an electrolyte suitable for bringing the body into the condition of a colloidal solution (sol-condition).

Hitherto the proportion of the added electrolyte has been. determined in relation either to the volume or the weight of the substance to which it is to be added. This rule gener-. ally leads to unfavorable results since the permissible maximum of added electrolyte is exceeded and the eifect thereby diminished. I have found, that the maximum permissible addition of electrolyte does not depend on the quantity and the weight of'the solid part or on the volume of the liquid in which it is suspended, but the most favorable addition of electrolyte depends on the superficies of the dispersoid, that is to say, under othermany materials.

into such relationship with the amount of added electrolyte, that the maximum of ad:

Patented May 1&, 1918. r

dition for a given degree of dispersion is attained. Here also the limit depends on commercial conditions, namely cost of comminution and cost of electrolyte.

When a body to be comminuted, such as steatite, is subjected to the operation in presence of the electrolyte, the latter has the eflect of rendering the comminution much more rapid and thorough. The body is to a certain degree opened up by the electrolyte. This favorable action is of further impor tance,-since, as already stated, the more electrolyte that can be added the greater the degree of dispersion of the solid substance. In this manner there is obtained a considerable increase in the dehydrating eii'ect per unit time and in the content of dry substance in the finished material.

I have found, that the favorable eflect of adding an electrolyte is not experiencedor only incompletely experienced in the case of The effect of the electro lyte can now be considerably increased by adding to the mass a colloid body in addition to an'electrolyte. Such bodies are, for instance, colloidal silicic acid, humic acid, organic and inorganic colloids. By adding bodies of this kind the eifect of the electro' lyte is increased. The colloidal body may be added to the mass before the electrolyte is added, or simultaneously therewith.

For example, in the treatment of steatite an addition of sodium silicate produces fatite and remains adsorbed. The behaviorin this case of the colloidal substances added to the electrolyte outside of the steatite depends upon the fact that these highly charged colloidal substances are adsorbed by the steatite and so function directly against the action of the electrolyte.

The sodium silicate is dissociated in water partly into sodium hydroxid and silicic acid (hydrolysis). The silicic acid is adsorbed Loses-so by the steetite though it is not certain Whether as ortho-, metha-, or poly-silicic acid. The sodium hydroxid represents the electrolyte.

The silicic acid adsorbed from the steetite is present in extraordinarily smell messes so that the steetite is obtained in an almost chemically pure condition. These small particles of silicic acid do no harm as the steatite itself is a magnesium silicate.

at I claim, is:

1. In a process for removing water from steetite, finely subdividing the steatite in the presence of an electrolyte suitable for bringing the solid body into sol-oondition and snbjeeting the steetite to the electro-osinotic treatment.

2. in a process for removing Water from steetite, finely subdividing the steetite in the presence of an electrolyte suitable for bringing the solid body into sol-condition, and of a colloid body, and subjecting the steetite to the elective-osmotic treatment.

3. in a process for removing Water from steetite subdividing the steetite in the pres enoe of sodium silicate and subjecting the steetite to the electro-osmotic treatment.

in testimony whereof 1 afin my signature in presence of two Witnesses.

BGTH O SCHVVIEREEN.

Witnesses error Greene, 

